Structural basis of bacterial transcription activation

Structural basis for transcription activation Bacteria can initiate transcription through two independent classes of recruitment mechanisms. Liu et al. determined the cryo-electron microscopy structure of an intact class I transcription activation complex. The positions and orientations of all the components and the detailed protein-protein and protein-nucleic acid interactions reveal how an activator interacts with the promoter DNA and recruits RNA polymerase through the class I mechanism. Together with a recently reported class II transcription activation complex, the findings complete our structural understanding of bacterial transcription activation. Science , this issue p. 947